The SX300 was originally designed by Ed Swearingen in San Antonio, TX. The aircraft was marketed as a kit from 1984 to 1989. By the end of 1989 approximately 80 kits had been sold, although there were only 48 sets of landing gear, which were built by the landing gear vendor, Airight Inc. in Wichita, KS.
The basic concept was to set new standards for Homebuilt or Amateur Built Aircraft as a dependable, fast mode of transportation; using all metal construction and proven techniques to provide an airframe that was equal to advanced jet aircraft.